Hi Britt,
Once the buyer and seller signed the contract and seller atty had released the contract, it's tricky situation. I will advised you to discuss with your atty for "what is the best thing for you". Good Luck..

A contract ,in Georgia, is not a valid contract until both parties have signed and a copy of the signed contract is delivered to both parties. Proir to that, a buyer may withdraw their offer. Also, most contracts have a due-diligence period, usually 10 days. This period is to give the buyer time to determine if there is a problem with the home or the loan. The buyer can withdraw the offer during this period.

Britt,
anybody can withdraw an offer at any time but the consequences of doing so depends on the the contract that has been signed, usually the buyer would loose their earnest money but like i said, it depends on the written contract. Now based on the idea that you made changes orally, then i would consult with your lawyer to see what would apply here.
i know it is much help but there is no much information and yes, it does happen

For an accurate answer and not knowing all the fine details, refer your question to your attorney, he will be your best source as he knows all the contract details.

Anna